Radiotherapy equipment used to perform treatment by irradiating an affected part within a subject with radiation is known. In radiotherapy, it is necessary to define a radiation dose to be radiated to a specific portion (affected part) and a position of a radiation source using a treatment planning device.
Here, a position of the affected part (specific portion) varies as time passes due to the subject's respiration or the like. Accordingly, it was also necessary to vary an irradiation position of radiation therewith and perform tracking irradiation of the specific portion. As technology used to perform tracking irradiation of a specific portion with radiation, technology for embedding a marker inside the subject, pre-measuring relative positions of the marker and the affected part using a computed tomography (CT) image or the like, and estimating the position of the affected part from relative positions to positions of a plurality of markers after a predetermined time is disclosed in Patent Literature 1.
In addition, technology used to compute a radiation dose radiated to the specific portion is disclosed in Patent Literature 2.